Monitoring refrigerant in a refrigeration system

• US 20070089436A1
• Filed: 10/21/2005
• Published: 04/26/2007
• Est. Priority Date: 10/21/2005
• Status: Abandoned Application

• Current Assignee: Emerson Retail Services, Inc. (Emerson Electric Company)
• Original Assignee: Emerson Retail Services, Inc. (Emerson Electric Company)
• Inventors: Singh, Abtar, Mathews, Thomas, Churiwal, Pawan
• Application Number:
  US11/256,639
• Publication Number:
  US 20070089436A1
• Time in Patent Office: Days
• US Class Current: 62/129
• CPC Class Codes: F25B 2500/19 Calculation of parameters
• CPC Class Codes: F25B 2500/28 Means for preventing liquid refrigerant entering into the compressor
• CPC Class Codes: F25B 2600/111 of condenser fans
• CPC Class Codes: F25B 2700/1931 Discharge pressures
• CPC Class Codes: F25B 2700/1933 Suction pressures
• CPC Class Codes: F25B 2700/195 of the condenser
• CPC Class Codes: F25B 2700/21151 at the suction side of the compressor
• CPC Class Codes: F25B 49/02 for compression type machines, plants or systems
• CPC Class Codes: F25D 2700/14 Sensors measuring the temperature outside the refrigerator or freezer
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

A method for monitoring refrigerant in a refrigeration system includes calculating a return gas superheat of a refrigeration system and averaging the return gas superheat over a predetermined period. The method also comprises comparing the average to a superheat threshold and detecting at least one of a flood back condition and a degraded performance condition based on the comparison. The method may be executed by a controller or stored in a computer-readable medium.

Claims

1. A method comprising:

calculating a return gas superheat of a refrigeration system;

averaging said return gas superheat over a predetermined period;

comparing said average to a superheat threshold; and

detecting at least one of a flood back condition and a degraded performance condition based on said comparison.

2. The method of claim 1, further comprising generating a notification based on said detecting.

3. The method of claim 1, further comprising:

receiving a suction pressure signal that corresponds to a suction pressure of a compressor of said refrigeration system;

receiving a suction temperature signal that corresponds to a suction temperature of said compressor; and

calculating a saturation temperature based on said suction pressure signal;

wherein said calculating said return gas superheat is based on a difference between said suction temperature and said saturation temperature.

4. The method of claim 1, wherein said superheat threshold is a predetermined flood back threshold, and wherein said flood back condition is detected when said return gas superheat is less than said flood back threshold.

5. The method of claim 4, wherein a notification is generated to notify of said flood back condition.

6. The method of claim 1, wherein said superheat threshold is a predetermined degraded performance threshold and wherein said degraded performance condition is detected when said average is greater than said degraded performance threshold.

7. The method of claim 6, wherein a notification is generated to notify of said degraded performance condition.

8. The method of claim 1, comprising:

calculating a superheat rate of change over time; and

comparing said superheat rate of change to a predetermined superheat rate of change maximum;

wherein said flood back condition is detected when said superheat rate of change is greater than said superheat rate of change maximum.

9. The method of claim 8, wherein a notification is generated to notify of said flood back condition.

10. The method of claim 1, further comprising:

calculating a superheat rate of change over time; and

comparing said superheat rate of change to a predetermined superheat rate of change minimum;

wherein said degraded performance condition is detected when said superheat rate of change is less than said superheat rate of change minimum

11. The method of claim 10, wherein a notification is generated to notify of said degraded performance condition.

12. A controller that executes the method of claim 1.

13. A controller that executes the method of claim 2.

14. A controller that executes the method of claim 3.

15. A controller that executes the method of claim 4.

16. A controller that executes the method of claim 5.

17. A controller that executes the method of claim 6.

18. A controller that executes the method of claim 7.

19. A controller that executes the method of claim 8.

20. A controller that executes the method of claim 9.

21. A controller that executes the method of claim 10.

22. A controller that executes the method of claim 11.

23. A computer-readable medium having computer executable instructions for performing the method of claim 1.

24. A computer-readable medium having computer executable instructions for performing the method of claim 2.

25. A computer-readable medium having computer executable instructions for performing the method of claim 3.

26. A computer-readable medium having computer executable instructions for performing the method of claim 4.

27. A computer-readable medium having computer executable instructions for performing the method of claim 5.

28. A computer-readable medium having computer executable instructions for performing the method of claim 6.

29. A computer-readable medium having computer executable instructions for performing the method of claim 7.

30. A computer-readable medium having computer executable instructions for performing the method of claim 8.

31. A computer-readable medium having computer executable instructions for performing the method of claim 9.

32. A computer-readable medium having computer executable instructions for performing the method of claim 10.

33. A computer-readable medium having computer executable instructions for performing the method of claim 11.